SheepDa

A Soft Functional Scripting Language

Weak and dynamically typed, statically bound, functional scripting language. Inspired by Lambda calculus with LISP/Scheme like syntax and features.

What do you mean by soft?

The language is very forgiving, and tries its best when operating on varying types. This makes it easier for a programmer to see what happens without running into runtime errors. For instance, what will subtrcating a number from a string mean? SheepDa will implicity cast the number to a string, and remove all instances of the substring. See examples for more use cases.

Usage

See HELP for menu

Syntax:

Each production follows Regex Format 
Note: Whitespace is ignored, unless in string literal
id	: [a-zA-Z]+[a-zA-Z0-9]*		// Identifier
stmt	: id=expr			// Binds expression to identifier
	| expr				// Stand-alone Expression
	| ; .* \n			// Comments, ends at newline
exprs 	: expr \s exprs
	| expr
expr	: (\\ id* \. expr )		// Defines an abstraction
	| (expr expr* )			// Applies expressions on the right to the leftmost expression
	| [0-9]+\.?[0-9]*		// Integer of Floating point number 
	| id 
	| \[ exprs \]			// List, Note: exprs are space seperated
	| ".*"				// String, anything encapsulated within quotes

Built-In Functions

Special Form

(if  a b c)	
(set i b)	
(while a b)	
(import a)
(exit a)

Math

(+ a b)
(- a b)
(* a b)
(/ a b)
(% a b)
(< a b)
(> a b)
(eq a b)
(root a b)
(exp a b)
(and a b)
(or a b)
(not a)

IO

(print a)
(read a [b ..] )

Type

(type a)
(int a)
(float a)
(string a)
(bool a)

List

(list a b )
(range a b)
(head l)
(tail l )
(reverse l )
(filter f l)
(fold f a l)
(map f l1 [l2 ... ])

Anonymous functions using the lambda operator.

x = ( \ x y . (+ x y ))		; Assign closed expression to x
(print (x 10 20))		; Prints 30, x->10
(print (\x y.(+ x y) 10 20))	; Also prints 30, lambda expression dynamically evaluated

p = print
(p "Hello")			; p is now a reference to print

Importing other files

(import "examples/fib.da") 	; Interprets the file at the relative directory of script

Builtin List features.

x = [ 1 2 3 4 5 6 7 8 9]	; Creates a list
y = (range 1 10)		; Creates a list = [1 .. 9]

(print (head x) )		; 1
(print (tail x) ) 		; [2 3 4 5 6 7 8 9]	

z = (map * x y ) 		; z = [ (* x[0] y[0]) ... (* x[9] y[9]) ]
(print z)			; [ 1 4 9 16 25 36 49 64 81 ]

w = (fold - 0 [ 1 2 3 4 5] ) 	; w = 1 - (2 - (3 - (4 - (5 - 0)))) = 3 

;Lists are lazy and evaluated when needed

l = [ (* 8 8 ) 3 "Hello"]	;l = [ (* 8 8 ) 3 "Hello"], literally
p = (head l)			;p = 64
(print p)			; 64

TODO:

FILE I/O applications
Derived expression to extend current functionality, such as case
Create a golfing ext - shorten builtin identifiers

138paulmiller/SheepDa